maxspeedaescending.java

数值算法例子,牛顿插值,拉格朗日,三次样条

/*@author 邱宇峰 ,software project031
 *2004,10,6
 */
import java.math.*;
import java.awt.*;
import java.awt.event.*;

public class maxSpeedAescending extends Frame implements ActionListener{
	static maxSpeedAescending frm=new maxSpeedAescending();
	static Button b;
	static Panel pl;
	static Label l;
	static TextField tf;
	public static void main(String[] args){
		frm.setTitle("最速下降法");
		b=new Button("click to start");
		l=new Label("Current Height is");
		tf=new TextField(20);
		pl=new Panel();
		pl.setLayout(new FlowLayout());
		pl.add(b); pl.add(l); pl.add(tf);
		frm.add(pl,"South");
		frm.setSize(700,700);
 		frm.setVisible(true);
		b.addActionListener(frm);
 		frm.addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent e){System.exit(0);}
		});
	}
	public void paint(Graphics g){
		/*
		for(double x=-212;x<212;x++){
			for(double y=-212;y<212;y++){
				if((x*x+y*y+2)<89890) {g.setColor(new Color(255,250,0));g.fillRect(10,105,30,10);}
				if((x*x+y*y+2)<62600) {g.setColor(new Color(255,200,0));g.fillRect(10,95,30,10);}
				if((x*x+y*y+2)<39764)  {g.setColor(new Color(255,150,0));g.fillRect(10,85,30,10);}
				if((x*x+y*y+2)<22474)  {g.setColor(new Color(255,100,0));g.fillRect(10,75,30,10);}
				if((x*x+y*y+2)<10084)  {g.setColor(new Color(255,50,0)); g.fillRect(10,65,30,10);}
				if((x*x+y*y+2)<5620)   {g.setColor(new Color(255,0,0));  g.fillRect(10,55,30,10);}	
				if((x*x+y*y+2)<2452)   {g.setColor(new Color(200,0,0));  g.fillRect(10,45,30,10); }
				if((x*x+y*y+2)<580)    {g.setColor(new Color(150,0,0));  g.fillRect(10,35,30,10);}
				if((x*x+y*y+2)<20)    {g.setColor(new Color(50,0,0));   g.fillRect(10,25,30,10);}
				g.drawString(".",320+(int)x,320+(int)y);}}		
		g.setColor(Color.black);
		g.drawString(""+(double)1/2.0032,40,35);
		g.drawString(""+(double)1/2.125,40,45);
		g.drawString(""+(double)1/2.5,40,55);
		g.drawString(""+(double)1/3.125,40,65);
		g.drawString(""+(double)1/4,40,75);
		g.drawString(""+(double)1/6.5,40,85);
		g.drawString(""+(double)1/10,40,95);
		g.drawString(""+(double)1/14.5,40,105);
		g.drawString(""+(double)1/20,40,115);
		*/
		double x=150,y=500,l=300;
		g.drawLine(150,500,150,180);
			while(y>=200){
				if(y<500&&y>450) {g.setColor(new Color(255,250,0));g.fillRect(10,160,30,10);}
				if(y<450&&y>400) {g.setColor(new Color(255,200,0));g.fillRect(10,150,30,10);}
				if(y<400&&y>350)  {g.setColor(new Color(255,150,0));g.fillRect(10,140,30,10);}
				if(y<350&&y>300)  {g.setColor(new Color(255,100,0));g.fillRect(10,130,30,10);}
				if(y<300&&y>275)  {g.setColor(new Color(255,50,0)); g.fillRect(10,120,30,10);}
				if(y<275&&y>250)   {g.setColor(new Color(255,0,0));  g.fillRect(10,110,30,10);}	
				if(y<250&&y>225)   {g.setColor(new Color(200,0,0));  g.fillRect(10,100,30,10); }
				if(y<225&&y>205)    {g.setColor(new Color(150,0,0));  g.fillRect(10,90,30,10);}
				if(y<205&&y>200)    {g.setColor(new Color(50,0,0));   g.fillRect(10,80,30,10);}			
				g.drawLine((int)x,(int)(y-=2),(int)x+(int)(l-=2),(int)y);
		}	
		g.setColor(Color.black);
		g.drawString(""+(double)1/2.0032,40,88);
		g.drawString(""+(double)1/2.125,40,98);
		g.drawString(""+(double)1/2.5,40,108);
		g.drawString(""+(double)1/3.125,40,118);
		g.drawString(""+(double)1/4,40,128);
		g.drawString(""+(double)1/6.5,40,138);
		g.drawString(""+(double)1/10,40,148);
		g.drawString(""+(double)1/14.5,40,158);
		g.drawString(""+(double)1/20,40,168);
		g.drawString(""+(double)1/2,150,200);
		g.drawString(""+(double)1/2.0032,150,210);
		g.drawString(""+(double)1/2.125,150,225);
		g.drawString(""+(double)1/2.5,150,250);
		g.drawString(""+(double)1/3.125,150,275);
		g.drawString(""+(double)1/4,150,300);
		g.drawString(""+(double)1/6.5,150,350);
		g.drawString(""+(double)1/10,150,400);
		g.drawString(""+(double)1/14.5,150,450);
		g.drawString(""+(double)1/20,150,500);
	}
		public void actionPerformed(ActionEvent h){
			Graphics g=getGraphics();
			calculatePartial cP=new calculatePartial();
			double x=-3,y=-3,result,e=0.01;
			while((result=Math.sqrt(cP.calculateGrade(x,y,0)*cP.calculateGrade(x,y,0)+cP.calculateGrade(x,y,1)*cP.calculateGrade(x,y,1)))>e){
				g.setColor(Color.blue);
				g.drawString(".",150-(int)(100*x),200-(int)(100*x));
				x=x+0.00999*cP.calculateGrade(x,y,0);
				y=y+0.00999*cP.calculateGrade(x,y,1);
				tf.setText(""+1/(x*x+y*y+2));
			}
			g.drawString("Max="+1/(x*x+y*y+2),300,200);
		}				
	}

class calculatePartial{
	double result,ac=0.001;
	double calculateGrade(double x,double y,int isParteXorY){
		if(isParteXorY==0){
			result=((1/((x+ac)*(x+ac)+y*y+2))-(1/(x*x+y*y+2)))/ac;
		}
		if(isParteXorY==1){
			result=((1/(x*x+(y+ac)*(y+ac)+2))-(1/(x*x+y*y+2)))/ac;
		}
		return (result);
	}
}